Las Vegas shooter Stephen Paddock wired $100,000 to an account in his live-in girlfriend’s home country of the Philippines in the week before he unleashed the worst mass shooting in modern U.S. history, according to multiple senior law enforcement officials.

But while officials have confirmed that Marilou Danley was in the Philippines on Sunday when Paddock opened fire on a crowd attending a country music festival on the Vegas Strip, it was not known whether the money was for her, her family, or another purpose.

Danley, 62, who had traveled to Hong Kong on Sept. 25, could fill in some of the blanks when she returns to the U.S. on Wednesday, the officials said. Her arrival airport was not known.

"We anticipate some information from her shortly," said Clark County Sheriff Joe Lombardo. "She is currently a person of interest."

Paddock's still-stunned brother, Eric Paddock, said he suspects the money was to take care of Danley.

"One hundred thousand dollars isn't that huge amount of money," he said. "Condemn Steve for gambling. Steve took care of the people he loved. He made me and my family wealthy."

Paddock may have "manipulated her so that she was far away from this and had money," Eric Paddock added. "As he was descending into hell...he wanted to take care of her."

Meanwhile, senior law enforcement officials told NBC News that Paddock gambled with at least $160,000 in the past several weeks at Las Vegas casinos.

There were 16 Currency Transaction Reports, or CTRs, filed for Paddock in recent weeks. The Treasury Department and the IRS mandate that casinos file the reports for "each transaction in currency involving cash-in and cash-out of more than $10,000 in a gaming day."

It could not be determined from the reports whether Paddock won or lost or both on the days in question. But they do show there were multiple transactions.

Paddock had "the highest status" at Caesars Entertainment properties in Las Vegas, a source close to the investigation told NBC News.

The top level for gamblers is Seven Stars Tier Status, which is by invitation only and subject to alteration or cancellation, according to the company's website. Privileges include comped rooms, room upgrades, player credits and access to "signature experiences."

But Paddock gambled and lost in 2012 when he filed a slip-and-fall lawsuit against another Vegas casino, the Cosmopolitan Hotel. In fact, he was still owed $270 in court fees when he killed himself and 59 other people on Sunday.

Lombardo credited local police and hotel security with the speed in which they reacted.

"What went right is we saved hundreds of lives," he said. "A lot more (deaths) were prevented."

Investigators believe Paddock and Danley started dating in spring 2017 and lived together in Mesquite. They do not believe she was involved in the shooting, although Paddock did have some of her identification on him, law enforcement officials have said.

Investigators still have not determined a motive for the mass murder. The death toll currently stands at 59 but officials have warned that could climb. More than 500 people were wounded.